For the production of cord twists, which generally consist of three threads, these three threads are guided through the delivery mechanism separately from one another and parallel to one another. Following the delivery mechanism the three threads run together at an acute angle at a uniting point and form a "thread cross." From the uniting point onwards begins the actual twisting of the three threads. Upon stopping of the frame an undesired effect occurs. Owing to the reducing thread tension in the twisting path the balance of the thread tensions is disturbed and the uniting point of the threads moves against the direction of movement of the threads towards the delivery mechanism. This motion of the uniting point is caused by the torsion stored in the threads. Upon motion of the thread cross the threads are partially unwound from one another and partially overwound, which imparts a corkscrew-like appearance to the twist. This corkscrew effect is undesirable since it spoils the appearance of the twist and moreover reduces the resistance of the twist to tearing, since the individual threads are not uniformly loaded when the twist is pulled.
In order to avoid the corkscrew effect as far as possible, hitherto only two threads have been guided under the drop stirrup of a thread breakage stopping device and the third thread was guided over the stirrup. In this way the motion of the thread cross could be stopped at the drop stirrup. In spite of this, however, the corkscrew effect occurred since the relationship to one another of the forces in the thread cross was unbalanced owing to the different modes of guiding the threads.
Mouline thread guides (so-called) are also known which are used in the production of multi-coloured twists, so-called Moulines. A known Mouline thread guide consists essentially of a horizontally arranged plate having two or more guide eyes arranged symmetrically to one another for the separate guiding of the threads to be twisted, which run together under the plate at an acute angle at a uniting point. Mixing of the various colours has to be avoided, i.e. the threads must always follow the same sequence in the finished twist. Also the use of such a Mouline thread guide in the production of cord twists is not a satisfactory solution. If upon stopping of the frame the thread tension falls, the uniting point of the three threads moves towards the underside of the plate of the Mouline thread guide. Here the threads then wind over one another and a knot-like form results by which likewise the resistance of the twist to tearing is reduced.
The invention is based on the problem of providing a thread guide for the production of cord twist, using the Mouline thread guide described, which prevents the formation of the corkscrew effect or the formation of knots and thereby permits the production of a cord twist which has the same quality and resistance over its whole length.
This is achieved in accordance with the invention by arranging on the underside of the plate between the guide eyes and symmetrically thereto a separating member the surface or surfaces of which converges or converge towards the uniting point and during the twisting process are spaced from the threads that are running together.
Surprisingly, it has been found that by means of such a separating member the corkscrew effect and the formation of knots can be avoided. Normally the individual threads run at a distance from the separating member, so that the separating member in no way adversely affects the running of the threads, does not rub the threads and itself undergoes no wear. Upon a reduction of the thread tension the uniting point runs upwardly oppositely to the direction of movement of the threads until it abuts the separating member. Since the separating member is arranged symmetrically or centrally relative to the guide eyes, upon motion of the thread cross there arise at the separating member the same conditions as regards the tensions and torsions in the individual threads and hence unwinding of the threads cannot take place.
Preferably the separating member projects from the underside of the plate so far downwardly that the threads that run on to the separating member upon reduction of tension are at an angle of at least about 45.degree. to the underside of the plate. If this angle is 45.degree. or more the formation of the knot or corkscrew effect is prevented with certainty.
The separating member is advantageously a ball or a half ball. If a ball is used, only the lower half-ball is effective as the new thread guide. The use of a ball has the advantage over a half ball only that balls are obtainable as commercial articles.